.popup__submit-button {
  background-color: #000;
  color: #fff;
  height: 3.125rem;
  font-size: 1.125rem;
  border: 0;
  border-radius: 0.125rem;
  margin-top: 0.2625rem;
  cursor: pointer;
  transition: background-color 0.35s linear;
  padding: 0;
}

.popup__submit-button:hover {
  background-color: rgb(0, 0, 0, 0.8);
}

@media screen and (max-width: 540px) {
  .popup__submit-button {
    height: 2.875rem;
    font-size: 0.875rem;
    margin-top: 1.35rem;
  }
}
